1、Designation: D7002 15D7002 16Standard Practice forElectrical Leak Location on Exposed Geomembranes Usingthe Water Puddle Method1This standard is issued under the fixed designation D7002; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice is a performance-based standard for an electrical method for locating leaks in exposed g
3、eomembranes. Forclarity, this practice uses the term “leak” to mean holes, punctures, tears, knife cuts, seam defects, cracks, and similar breaches inan installed geomembrane (as defined in 3.2.5).1.2 This practice can be used for geomembranes installed in basins, ponds, tanks, ore and waste pads, l
4、andfill cells, landfill caps,canals, and other containment facilities. It is applicable for geomembranes made of materials such as polyethylene, polypropylene,polyvinyl chloride, chlorosulfonated polyethylene, bituminous geomembrane, and any other electrically insulating materials. Thispractice is b
5、est applicable for locating geomembrane leaks where the proper preparations have been made during the constructionof the facility.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to addres
6、s all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4439 Terminology
7、for GeosyntheticsD6747 Guide for Selection of Techniques for Electrical Leak Location of Leaks in GeomembranesD7703 Practice for Electrical Leak Location on Exposed Geomembranes Using the Water Lance Method1 This practice is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the di
8、rect responsibility of Subcommittee D35.10 on Geomembranes.Current edition approved Jan. 1, 2015Jan. 1, 2016. Published January 2015January 2016. Originally approved in 2003. Last previous edition approved in 20102015 asD7002D700210.-15. DOI: 10.1520/D7002-15.10.1520/D7002-16.2 For referencedASTM st
9、andards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an
10、 ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as publis
11、hed by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D7953 Practice for Electrical Leak Location on Exposed Geomembranes Using the Arc Testing Method3. Terminology3.1 Definitions:3.1.1
12、For general definitions used in this practice, refer to Terminology D4439.3.2 Definitions of Terms Specific to This Standard:3.2.1 artificial leak, nan electrical simulation of a leak in a geomembrane.3.2.2 conductive-backed geomembrane, na specialty geomembrane manufactured using coextrusion techno
13、logy featuring aninsulating layer in intimate contact with a conductive layer.3.2.3 current, nthe flow of electricity or the flow of electric charge.3.2.4 electrical leak location, na method which uses electrical current or electrical potential to locate leaks.3.2.5 leak, nfor the purposes of this d
14、ocument, a leak is any unintended opening, perforation, breach, slit, tear, puncture,crack, or seam breach. Significant amounts of liquids or solids may or may not flow through a leak. Scratches, gouges, dents, orother aberrations that do not completely penetrate the geomembrane are not considered t
15、o be leaks. Types of leaks detected duringsurveys include, but are not limited to: burns, circular holes, linear cuts, seam defects, tears, punctures, and material defects.3.2.6 leak detection sensitivity, nthe smallest leak that the leak location equipment and survey methodology are capable ofdetec
16、ting under a given set of conditions. The leak detection sensitivity specification is usually stated as a diameter of the smallestleak that can likely be detected.3.2.7 poor contact condition, nfor the purposes of this practice, a poor contact condition means that a leak is not in intimatecontact wi
17、th the conductive layer above or underneath the geomembrane to be tested. This occurs on a wrinkle or wave, under theoverlap flap of a fusion weld, in an area of liner bridging and in an area where there is a subgrade depression or rut.3.2.8 probe, nfor the purposes of this practice, any conductive
18、structure that is attached to a power source.3.2.9 squeegee, nfor the purposes of this document, a squeegee is a device used to contain and push water on top of anexposed geomembrane. It may consist of a handle and a transverse piece at one end set with a strip of leather or rubber, or a rollerappar
19、atus.3.2.10 water puddle, na small pool of water placed on the geomembrane to create a conduit for current to flow through anyleaks.4. Significance and Use4.1 Geomembranes are used as barriers to prevent liquids from leaking from landfills, ponds, and other containments. For thispurpose, it is desir
20、able that the geomembrane have as little leakage as practical.4.2 The liquids may contain contaminants that, if released, can cause damage to the environment. Leaking liquids can erode thesubgrade, causing further damage. Leakage can result in product loss or otherwise prevent the installation from
21、performing itsintended containment purpose.4.3 Geomembranes are often assembled in the field, either by unrolling and welding panels of the geomembrane materialtogether in the field, unfolding flexible geomembranes in the field, or a combination of both.4.4 Geomembrane leaks can be caused by poor qu
22、ality of the subgrade, poor quality of the material placed on the geomembrane,accidents, poor workmanship, manufacturing defects, and carelessness.4.5 Electrical leak location methods are an effective and proven quality assurance measure to detect and locate leaks.5. Summary of Exposed Geomembrane E
23、lectrical Leak Location Methods5.1 Principles of the Electrical Leak Location Methods for Exposed Geomembranes:5.1.1 The principle of the electrical leak location methods is to place a voltage across a geomembrane and then locate areaswhere electrical current flows through leaks in the geomembrane.5
24、.1.2 Currently available methods include the water lance method (Practice D7703), the arc testing method (Practice D7953),and the water puddle method.5.1.3 All of the methods listed in 5.1.2 are effective at locating leaks in exposed geomembranes. Each method has specific siteand labor requirements,
25、 survey speeds, advantages and limitations. A professional specializing in the electrical leak locationmethods can provide advice on the advantages and disadvantages of each method for a specific project.5.1.4 Alternative ASTM Standard Practices for electrical leak location survey methods should be
26、allowed when mutuallyagreeable and warranted by adverse site conditions, clearly technical superiority, logistics, or schedule.6. Water Puddle Method6.1 A summary of the method capabilities and limitations is presented in Table 1.NOTE 1If used, conductive-backed geomembrane must be installed per the
27、 manufacturers recommendations in order to allow it to be tested usingD7002 162all of the available electrical leak location methods. In particular, there must be some means to break the conductive path through the fusion welds alongthe entire lengths of the welds, the undersides of adjacent panels
28、(and patches) should be electrically connected together, and a means of preventingunwanted grounding at the anchor trenches or other unwanted earth grounds should be provided.6.2 Principle of the Water Puddle Method:6.2.1 Fig. 1 shows a diagram of electrical leak location using the water puddle meth
29、od for exposed geomembranes. One outputof an electrical excitation power supply is connected to an electrode placed in a water puddle created on top of the geomembrane.The other output of the power supply is connected to an electrode placed in the electrically conductive material under thegeomembran
30、e.6.2.2 Measurements are made using an electrical current measurement system. An electronic assembly is used to produce anaudio tone whose frequency is proportional to the current flow.6.3 Leak Location Surveys of Exposed Geomembrane Using the Water Puddle Method:6.3.1 The water puddle leak location
31、 method usually consists of a horizontal water spray manifold with multiple nozzles thatspray water onto a geomembrane, a squeegee device to push the resultant puddle of water, and a handle assembly as shown in Fig.1. A pressurized water source, usually from a tank truck parked at higher elevation,
32、is connected to the spray manifold using aplastic or rubber hose.6.3.2 Direct current power supplies (usually a 12 to 36 volt battery or series of batteries) have been used for leak locationsurveys. An alternating current (output requirement of 12 to 30 volt ac) could be used.6.3.3 For leak location
33、 surveys of exposed geomembrane, the water puddle created is pushed systematically over thegeomembrane area to locate the points where the electrical current flow increases.6.3.4 The signal from the probe is typically connected to an electronic detector assembly that converts the electrical signal t
34、oan audible signal that increases in pitch and amplitude as the electrical current increases.6.3.5 When a leak signal is detected, the location of the leak is then marked or measured relative to fixed points.6.3.6 The leak detection sensitivity can be very good for this technique. Leaks smaller than
35、 1 mm in diameter are routinelyfound, including leaks through seams in the geomembrane.TABLE 1 Summary of Water Puddle MethodGeomembranes Bituminous, CSPE, CPE, EIA, fPP, HDPE, LLDPE, LDPE, PVC, VLDPE U applicableConductive-backed Geomembrane U applicableASeams All types: welded, tape, adhesive, glu
36、ed and other U applicable: project specificJunctions At synthetic pipes and accessories U applicable: project specificAt grounded conducting structures X not applicableSurvey During construction phase (installation of GM) U applicableAfter installation (exposed) U applicableSlopes U applicable: proj
37、ect specificInsufficiently conductive subgrade X not applicableDuring the service life (if exposed) U project specificClimate Sunny, temperate, warm U applicableRainy weather X not applicableFrozen conditions X not applicableLeaks detected Discrimination between multiple leaks U applicableA If used,
38、 conductive-backed geomembrane must be installed per the manufacturers recommendations in order to allow it to be tested using all of the available electricalleak location methods. In particular, there must be some means to break the conductive path through the fusion welds along the entire lengths
39、of the welds, the undersidesof adjacent panels (and patches) should be electrically connected together, and a means of preventing unwanted grounding at the anchor or other unwanted earth groundsshould be provided.FIG. 1 Diagram of the Water Puddle MethodD7002 1636.3.7 The survey rate depends primari
40、ly on the manifold and squeegee width and the presence of wrinkles and waves in thegeomembrane.6.4 Preparations and Measurement Considerations:6.4.1 Proper field preparations and other measures shall be implemented to ensure that an electrical connection to the sufficientlyconductive material direct
41、ly below the geomembrane is in place to successfully complete the leak location survey.6.4.2 There shall be a sufficiently conductive material below the geomembrane being tested. A properly-prepared subgradetypically will have sufficiently conductivity. Under proper conditions and preparations, geos
42、ynthetic clay liners (GCLs) can beadequate as conductive material. There are some other conductive layers such as conductive geotextiles and aluminum foils withsuccessful field experience which can be installed beneath the geomembrane to facilitate electrical leak survey (that is, on drysubgrades, o
43、r as part of a planar drainage geocomposite).6.4.3 Measures should be taken to perform the leak location survey when geomembrane wrinkles are minimized. If a hole islocated on a wrinkle, then this poor contact condition may result in an undetected leak. The leak location survey should beconducted at
44、 night or early morning when wrinkles are minimized. Sometimes wrinkles can be flattened by personnel walking orstanding on them as the survey progresses.6.4.4 Conversely, surveys should not be made in areas with bridging geomembrane. The survey of areas with minor bridgingmight be accomplished when
45、 the geomembrane is warmer.6.4.5 For lining systems comprised of two geomembranes with only a geonet or geonet geocomposite between them, to makethe method feasible a sufficiently conductive layer such as a conductive geotextile, conductive geocomposite, aluminum foil, orany appropriate conductive m
46、aterial shall be installed under the geomembrane or integrated into the geonet geocomposite.Conductive-backed geomembrane can also be used as the primary geomembrane to enable the method. See Guide D6747.6.4.6 For best results, conductive paths such as metal pipe penetrations, pump grounds, and batt
47、en strips on concrete should beisolated or insulated from the water puddle on the geomembrane. These conductive paths conduct electricity and mask nearby leaksfrom detection.6.4.7 The water puddle applied to the geomembrane should not be allowed to flow out of the survey area, connecting the waterto
48、 the ground of the power supply. The results in a false positive signal and will compromise survey sensitivity.6.4.8 Depending on specific construction practices and site conditions, other preparations and support may still be needed tosuccessfully perform the leak location survey.6.5 Practices for
49、Surveys with the Water Puddle Method6.5.1 A realistic test of the leak detection sensitivity shall be performed and documented as part of the leak location survey. Anactual or artificial leak can be used. The leak location equipment and procedures should be demonstrated to be able to detect theartificial or actual leak when water puddle is passed over the leak on the geomembrane.6.5.2 Artificial LeakAn artificial leak may consist of the cut end of an insulated solid core or stranded wire, with a crosssection no larger than 1.0 mm diameter, IEC 0.75 mm2 or 18 AWG. Th
